On Mon, 29 Nov 2004 07:39:39 +1100, "Benjamin Herrenschmidt" said: > On Sun, 2004-11-28 at 21:14 +0100, Frank Murphy wrote: > > On Sunday 28 November 2004 2:58, Benjamin Herrenschmidt wrote: > > > > > > > > So I've tried this using the stock Debian 2.6.8 and 2.6.9 PPC kernels > > > > with the same results. > > > > > > > > $ grep ATY /boot/config-2.6.9-powerpc > > > > CONFIG_FB_ATY128=y > > > > CONFIG_FB_ATY=y > > > > CONFIG_FB_ATY_CT=y > > > > CONFIG_FB_ATY_GX=y > > > > # CONFIG_FB_ATY_XL_INIT is not set > > > > > > > > It seems that the atyfb module is compiled in. Is there another way to > > > > check? > > > > > > Check the bits in CONFIG_PMAC_BACKLIGHT in atyfb (like, add some > > > printk's to see if they are reached etc..) > > > > So I added a couple of printk()s like you asked. I added one to > > aty128fb_blank() in aty128fb.c:2037 and two to aty_init() in > > atyfb_base.c:1793 and 1802 (inside the 'if (M64_HAS(MOBIL_BUS))'). The one > > I > > added to aty128fb didn't print (as expected), but both of them from > > atyfb_base.c printed. So it seems that CONFIG_PMAC_BACKLIGHT is properly > > defined. Anything you'd specifically like me to try? > > Well, the backlight control is done by writing to one of the LCD > register, you can try to track down the values in there and eventually > compare with 2.4
I'll try to look at this, but I don't know very much about it. > > I find it interesting that in the console the dimming works. I thought that > > on > > PPC the console used the framebuffer. Another notable thing is that while > > in > > X, the dimming doesn't work, but when I switch to one of the VTs, the > > screen > > brightness is adjusted to what it should have been in X. > > Ah ? What do you mean by "dimming" ? blanking ? or backlight control ? OK, the F1 and F2 keys on my keyboard have little "brighter"/"dimmer" icons on them. When I press them when running X on 2.4.25, the screen brightness changes. So for me, that's "dimming." I believe that it's the "backlight control" that does this. When I press the "dimmer" button enough (8 times, I think), then the backlight turns totally off, and I can't see anything on the screen. For me that's "blanking" in this context. It's true that something else (X, I think) will kind of blank the screen, but the backlight stays lit. I noticed this when I closed the lid to make the iBook sleep, but the backlight stayed on, warming the keyboard. I then noticed the same problem with the dimmer keys. > Could be some crap done by the X driver ... It's notoriously allergic to > fbdev's ... I'll have to double check. It probably is. But it's strange because I use all the same software except the kernel to get this behavior. So there's something with the kernel / X interface that has changed, either for 2.6 or the way Debian builds 2.6. I have a hard time with this because there are so many interactions: is it the PMU? The APM emulation? X driver? Kernel driver? I don't have a good idea about how these things interact. Let me know what you find out. Frank
